Eyewear frame assemblies often need to be impact resistant, such as when worn for sporting activities. ASTM F803 is a stringent standard governing impact resistance requirements for eyewear worn during sporting activities. Polycarbonate is the material of choice for eyewear frames meeting the ASTM F803 requirements. That is used for non Rx-able frames known as Plano frames, no prescription lenses. For prescription eyewear, there needs to be a way to insert the lenses and still maintain the impact strength of the material. Heating of the eyerim of a frame is the known norm for the insertion of lenses into plastic sport frames. Heating of most eyewear frame materials, such as polycarbonate, to insert lenses in the eyewear frames destroys the impact resistance strength of the frames. Some materials are extremely resistant to heat, thereby preventing heating as an option for inserting lenses in the eyewear frames. Still other materials require an excessively thick eyewear frame to meet the impact resistance requirements, so that the resulting eyewear frames are aesthetically undesirable, bulky and awkward for wearers. A need exists for eyewear frames that allow for insertion of lenses without affecting the impact resistance of the eyewear frames and still provide aesthetically pleasing and efficient eyewear frames.
Eyewear frames in which lenses can be easily inserted and still withstand impact are greatly desired by wearers. Heating frames to insert lenses and still maintain impact usually requires the frame to be bulky. Eyewear frames exist that allow the wearer to remove and insert lenses. However, most existing eyewear frames do not provide the impact resistance required by ASTM F803. Wearing such eyewear frames during a sporting activity could result in serious injury to wearers if the frames and lenses are not able to sustain impacts. A need exists for eyewear frames that allow for easy insertion and removal of lenses, while still meeting the impact resistance requirements for use during sporting activities.
Thus, there is a continuing need to provide improved eyewear frame assemblies.